Background: Controversy still exists about the role and timing of endoscopic retrograde cholangiopancreaicotography (ERCP) in mild to moderate biliary pancreatitis. Routine preoperative ERCP detects persisting common bile duct stones but is associated with definite morbidity and may delay definitive care. Aim of study : The study aims to evaluate the role of ERCP in the management of mild to moderate acute biliary pancreatitis. Patients and methods : The records of 196 patients with diagnosis of mild to moderate acute biliary pancreatitis (ABP) were retrospectively reviewed over four-years period. The various parameters examined were age, sex, clinical presentation, laboratory values, radiological studies, and severity of the attack, preoperative ERCP, surgical intervention and length of hospital stay. Pre operative ERCP was performed in 136 (67%) patients. Indications of ERCP were presence of jaundice, dilated common bile duct on ultrasonography, persistent hyperamylasemia, and associated cholangitis. In 17 patients with old age and multiple medical problems, ERCP served as a definite procedure. Results: Mild to moderate cases accounted for 91% of ABP. Liver function tests (bilirubin, ALP, AST, ALT) were raised in 64% of cases. persistent hyperamylasemia in 4%, dilated CBD was observed in 14% associated cholangitis was present in 11%. Preoperative ERCP was positive in 22 (16%) patients, only where a CBD stones could be found and an endoscopic sphincterotomy) (ES) was performed. Positive predictive values were 25% for the high bilirubin level, 22% for the high ALP level, 50% for the persistent hyperamylasemia, 57% for the dilated CBD, 45% for the associated cholangitis. ERCP was associated with a morbidity rate of 3.6% with no mortality. The procedure was regarded as unnecessary in 84 % of cases, where it increased the length of hospital stay by a mean of 2, 3 days. Conclusion : Preoperative ERCP was therapeutic in only 16% in cases of mild to moderate ABP. It should be done only on selective basis. In elderly patients with multiple medical problems. ERCP and ES can serve as definitive treatment

Keywords: acute biliary pancreatitis, ERCP.

How to cite this article:Al Salarnah SM, Bismar HA. Role of preoperative endoscopic retrograde cholangio pancreaticography in the management of mild to moderate acute biliary pancreatitis. Saudi J Gastroenterol 2002;8:85-92

Acute Biliary pancreatitis (ABP) is the most common type of acute pancreatitis and accounts for 50-70% cases[1] . It is due to migration of gallstone and transient blockage of the common channel entering the ampulla of Vater[1] . Management of acute biliary pancreatitis comprises of two principles. The first is to extract the offending stone endoscopically. The second is eradication of the gallstones by cholecystectomy[2] . Controversy exists about doing preoperative ERCP routinely in mild to moderate of ABP. Many reports suggested the routine preoperative ERCP to clear the CBD before laparoscopic cholecystectomy[1],[3].In fact the stones could be retrieved in only 18% cases[4] . Other studies questioned the role of routine preoperative ERCP, as 85-90% of patients will improve clinically as the stone pass spontaneously[5],[6] This study aimed to evaluate the role of preoperative ERCP in the management of mild to moderate cases of ABP.

Patients and Methods

From May 1st 1998 through April 30th 2002, a total of 266 patients were admitted to Riyadh Medical Complex (a tertiary referral center) with diagnosis of acute pancreatitis. The diagnosis of acute biliary pancreatitis (ABP) was confirmed in 215 patients. The medical records of all those patients were reviewed for age, clinical presentation, biochemical and radiological investigations, timing and result of endoscopic retrograde cholangiopancreaticography (ERCP), surgical procedure and hospital stay.

The diagnosis of ABP was confirmed by the presence of upper abdominal pain, elevated serum amylase level (thrice more than normal value of 25­115 IU), the presence of gallstones on ultrasonography (USG) and absence of hypercalcemia or hyperlipidemia. All the patients had abdominal ultrasonography with specific comments on presence of common bile duct (CBD) stone and duct diameter. Contrast enhanced computed tomography (CT) of the abdomen was done in cases, where the diagnosis was uncertain and in predicted severe pancreatitis.

The ABP was regarded as "severe" in the presence of organ failure (hypotension < 90mm Hg systolic BP, tachypnoea with p02 < 60mm Hg, low urine output with high creatinine) or local complications (necrosis, fluid collection, pseudocyst or abscess) according to Atlanta clinically based classification of acute pancreatitis[7] . Nineteen patients were considered as severe ABP and excluded from the study. The remaining 196 patients with mild to moderate attack were further evaluated. ERCP was performed in 136 (69%) of patients with mild to moderate ABP. Various indications of ERCP were impaired liver functions on admission and dilated CBD on USG. The biochemical and radiological data were analyzed to analyze positive predictive values for the presence of CBD stones. The predictive clinical and biochemical factors evaluated were hyperbilirubinemia, elevated alkaline phosphatase, persistent hyperamylasemia and presence of cholangitis (fever more than 38.5° C, leukocytosis). The radiological factors were CBD diameter more than 7mm on USG or presence of stone inside the biliary tree. Timing of ERCP from the day of admission and the onset of the attack were also studied.

Hundred thirty eight patients (70%) with mild to moderate pancreatitis underwent laparoscopic cholecystectomy at the index admission after clinical and biochemical resolution of ABP. As the facilities of laparoscopic CBD exploration are not available the intraoperative cholangiogram (IOC) was not performed routinely during laparoscopic cholecystectomy.

Results

Among a total of 266 patients admitted with acute pancreatitis, the diagnosis of ABP was confirmed in 215 patients, which accounted for 80% of cases. Eighty-four patients (40%) were male, and 131 were female (60%). The mean age was 36 year (range 17­93 yrs). The ABP was regarded as mild to moderate in 196 patients; it accounted for 91% of cases, which are the subject of this study. The results of various biochemical values are shown in [Table - 1]. Abnormal liver function tests (bilirubin, AST, ALT, ALP) on admission were detected in 125 patients (64%). Twenty-two patients had associated cholangitis (fever more than 38.5° C and leukocytosis). Abdominal USG done in all patients showed gallstones in 188 patients (96%), dilated CBD was found in 27 patients (14%), CBD stones were identified in only two patients. Five patients were postcholecystectomy.

The ERCP was performed in 136 patients (69%) and CBD stones were retrieved in only 22 patients. ERCP was therapeutic in only 16% of the patients [Figure - 1],[Figure - 2] It was done at mean of 2.7 days after admission (ranges 1-7 days), and a mean of 4.4 days after the onset of the attack (range 2-8 days). Four patients were found to develop mild to moderate ABP as a result of retained CBD stone post­cholecystectomy. All had raised liver enzymes and bilirubin, with a dilated CBD on USG (>7mm). ERCP was done in all these patients and stones were extracted in three patients. In cases of post­cholecystectomy there is no debate about ERCP indication as almost all the patients have a retained CBD stone.

In the rest 60 patients (31%), with mild to moderate pancreatitis, raised serum amylase (> 4 times) was found in all patients (100%), abnormal liver function tests were observed in 42 patients (70%), and none of the patients had CBD dilatation or CBD stones demonstrated on ultrasonography. Multiple gallstones were reported in all of these patients signifying the diagnosis of the biliary pancreatitis. ERCP was not performed in these patients due to lack of clear indications. None of these patients developed any complications with continued conservative management. All these patients were subjected to laparoscopic cholecystectomy in the index admission. The mean hospital stay in these patients was three days (ranges 1-5 days) less than those who were subjected to ERCP.

[Table - 2] shows the frequency of the predictive factors of CBD stones in all patients, who underwent ERCP and its positive predictive values. The positive predictive values for presence of CBD stones were 100% for presence of CBD stone, 57% for CBD diameter more than 7mm, 50% for persistent high serum amylase level after four days of admission, 45% for associated cholangitis, 25% for persistent high bilirubin level at the day before ERCP, and 22% for high alkaline phosphatase (ALP) level.

ERCP was complicated by exacerbation the AP in two patients, both responded to conservative measures. One patient had bleeding from ES site treated with blood transfusion. Two patients developed cholangitis, which responded to antibiotics. There was no death related to the procedure itself. The ERCP in this study was associated with morbidity rate of 3.6%, with no mortality. ERCP lead to increase the hospital stays 2-3 days more than patients who didn't have the procedure.

Hundred thirty eight patients with mild to moderate ABP were subjected to laparoscopic cholecystectomy at the index admission after clinical and biochemical resolution of the attack between 4-7 days after admission, with mean postoperative hospital stay of two days (1-7 range). The other 58 patients were not operated, five patients were post­cholecystectomy, in 17 elderly patients (age >70 years) ERCP and ES served as definitive treatment, ten patients with multiple medical problems were high risk for surgery and they were followed in outpatients clinic for possible elective cholecystectomy, 18 patients preferred the delayed surgery, eight patients with no gall stones on USG were discharged and followed up in the outpatient clinic with repeat USG.

Discussion

ABP is due to gall stone migration with transient blockage of the ampulla of Vater as suggested by Acosta in 1974.[6] Stones were found in feces of 94% of their patients within ten days of the attack. In the western society, the gallstones and alcohol abuse are the most important causes of AP accounting for 65-80% of cases[1] . The present study reveals biliary pancreatitis as the most common type of acute pancreatitis in central region of Saudi Arabia, accounting for 80% of all cases. These results are consistent with other studies in Saudi Arabia and may be explained by the prohibition of alcohol use in the Kingdom.[8],[9]

The clinical spectrum of ABP ranges from mild self-limiting to a fulminate rapidly lethal disease. Assessment of severity of AP is an essential factor in the management. The pancreatitis associated with gallstones is mild in 75-97% of cases[10],[11] . ABP is seen in 8-25% of patients and the majority of the complications occurred in such severe forms of ABP and is responsible for 95% of ABP related mortality. In this study 91% of patients had mild to moderate attack and only 9% developed severe ABP.

Many scoring systems were suggested to evaluate the severity of AP. Ranson in 1982 suggested 11 prognostic criteria[11] . Balthazar et al used the presence of pancreatic necrosis on CT as a marker of severity[12] . In 1992 Atlanta symposium a new clinically based classification of acute pancreatitis was developed with the conclusion that severity should be defined by the presence of organ failure, local complications (including necrosis, pseudocyst, and abscess) or both[7] . We found Atlanta's criteria easier to use in clinical practice than Ranson's criteria, which need to wait 48 hours to achieve the assessment, and by this time the biochemical values may get influenced with adequate resuscitation of the patients[13],[14]

Since Safrany et al in 1980 recommended ERCP and ES for the treatment of ABP, a lot of controversies exist about the role and timing of ERCP in the management of ABP[3] . Neoptolemos et al advocated urgent ERCP and ES for management of ABP to clear the CBD stones[15] . This consensus was supported as well by another randomized trial by Fan et al[16] Stone et al showed a reduction in mortality rate of ABP from 6% to 3% with emergency ERCP and ES within 27 hours of admission[17]

The present study showed a low proportion (16%) of CBD stones in mild to moderate ABP. This result is similar to many recent studies. Bulkin et al found a low incidence of CBD stones in ABP and concluded that routine preoperative ERCP was not indicated[4],[6],[18] The majority of CBD stones in the urgent ERCP group would have passed harmlessly without intervention[5] . Patients undergoing urgent ERCP had a 50% incidence of CBD stones, whereas patients with conservative treatment that consisted with selective delayed ERCP had only 11 incidence of CBD stone[18] . Waiting 3-5 days, the chance of finding associated CBD stones are decreased from approximately 70% on the day of admission to 20% by the 4 th day[19]. This may explain our results in that the ERCP was done after a mean of 4.4 days.

Recent studies by Fan et al found that early removal of CBD stone did not appreciably alter the course of mild to moderate pancreatitis[15] . Same conclusion was confirmed by Folsch et al, who demonstrated that patients without obstructive jaundice or biliary sepsis did not benefit from urgent FRCP- and ES[20] . Another two reports supported doing ERCP on selective basis in cases of mild to moderate ABP[21],[22]

Factors predictive of CBD stones in the absence of pancreatitis include a dilated CBD and elevated serum bilirubin and ALP[23] . However, these criteria may not apply to patients with ABP as liver enzymes are elevated on admission to some degree in a large majority of the cases[5] . The positive predictive values in our study were 25% for the high bilirubin level on admission, 22% for the high ALP, and 57% for the dilated CBD. Vigilio et al reported a positive predictive value of 31% for persistent hyperbilirubinemia to greater than 29 micromole/L (normal, 17), 60 % for persistent hyperamylasemia to greater than 150 u/L, 44% for the dilated CBD stones, 80% for associated cholangitis, 100% for visualization of CBD stone on USG[5] .

ERCP hazards and complications may develop in 3-6.4% of patients[24],[25] . In this study ERCP was complicated in five cases with morbidity rate of 3.6% and 0% mortality. Chang et al showed that in patients with mild to moderate ABP selective ERCP was associated with a shorter hospital stay, less cost, and significant reduction in ERCP use compared with routine preoperative ERCP[26] .

Intraoperative cholangiography (IOC) is another alternative to ERCP. Identification of CRD stone on IOC will necessitate CBD exploration either laparoscopically or at postoperative ERCP[21] . We reserved IOC to the cases, where open CBD exploration was needed because of ERCP failure and in cases, where laparoscopic cholecystectomy was converted to an open procedure. Al Qasabi et al concluded that ERCP either pre- or postoperative could replace the IOC[27] . Laparoscopic CBD exploration needs skillful laparoscopic surgeon and high technology. There are many reports, which showed high success rates with this technique. Open CBD exploration increases the length of hospital stay in comparison to ERCP[21]. Till the facilities of CBD laparoscopic exploration become available, a suspected CBD stones on IOC can be managed successfully with postoperative ERCP. Dobromir et al reported a high successful in removing retained biliary calculi (100% success rate)[28] . Sbeih et al from Saudi Arabia quoted similar results[29] .

[Table - 3] shows a collected series with frequency of ERCP and IOC as diagnostic tools, and the different ways of CBD stones removal endoscopically during preoperative ERCP, or CBD exploration using either laparoscopic common duct exploration (LCBDE) or the conventional open technique (OCBDE). In 17 patients we used the ERCP as definitive treatment due to old age and multiple medical problems. In selected patients with multiple medical problems, ERCP and ES may serve as a definitive therapy because only approximately 10% will require further intervention[30] .

Conclusion

We concluded that the preoperative ERCP should be done selectively in mild to moderate cases of ABP. where there are persistent elevated bilirubin and liver enzymes, which do not promptly return back (within 3-4 days), persistent high amylase level, dilated CBD on USG, in order to clear the CBD before laparoscopic cholecystectomy. ERCP can serve as a definitive treatment in the elderly patients who are at high risk for surgery.[32]